achate collection was assumed active throughout the entire 100- year time period of the assessment; however, a worst case situation was considered assuming a progressive deterioration of the bottom liner performance. This resulted in decreasing leachate collection efficiency over time: from 95% efficiency during the first 20 years to 60% the last 25 years. The first 50 years all collected leachate was assumed to be treated at a wastewater treatment plant (WWTP), in the latter period all collected leachate was assumed to be discharged directly to the sea. Sludge from the WWTP (containing the removed heavy metals) was assumed distributed at fields and the heavy metals accordingly ending up as soil emissions. The WWTP was not assumed to be 100% efficient and specific heavy metals removal efficiencies were applied in the WWTP based on Manfredi and Christensen
(2009). The heavy metals not removed at the WWTP were assumed discharged to surface waters, whereas heavy metals in the non- collected leachate ended up in the groundwater (Manfredi and Christensen, 2009).
Air emissions from the specific thermal treatment processes (Scenarios 6 and 7) were not available but were instead estimated based on element transfer coefficients for typical waste incinerators (i.e. fractions of an element in the input emitted to air, see Riber et al.,
2008). The solid composition of the APC residues as shown in Table 2 was used as input. In Scenario 7, the residues were co-treated with automobile shredder residues and the transfer coefficients were applied to this mixture. The transfer coefficients were within the range 0–0.35 corresponding to incineration in a modern MSW incinerator (Riber et al., 2008; Pedersen et al., 2009).
Electricity and heat consumed or substituted within the scenarios were assumed to be produced at combined heat and power plants using coal as fuel. Assumptions regarding energy may potentially be important; however the choice of coal as fuel for energy production follows common practice within LCA (for further details, refer to Fruergaard et al., 2009). The emissions and fuel consumptions at these plants were typical for Danish conditions and allocated based on energy quality, i.e. based on an assumption that electricity has a higher quality than heat and
4675
thereby associated with a relatively larger share of the emissions and fuel consumption (Fruergaard et al., 2009). The environmental load of electricity generation was thereby approximately six times higher than heat generation. Energy and resource consumption/ substitut
ชุด achate ถือว่าใช้ได้ทั่วทั้งหมดระยะเวลา 100 ปีของการประเมิน อย่างไรก็ตาม สถานการณ์กรณีที่เลวร้ายที่สุดถือเป็นสมมติว่าเสื่อมสภาพที่ก้าวหน้าทำงานซับด้านล่าง ส่งผลให้ลด efficiency คอลเลกชัน leachate เวลา: จาก efficiency 95% ระหว่าง first ปี 20% 60 ปี 25 first 50 ปี leachate รวบรวมทั้งหมดถูกถือว่าได้รับการรักษาที่โรงบำบัดน้ำเสีย (WWTP), ในระยะหลัง leachate รวบรวมทั้งหมดไม่ถือจะปล่อยออกสู่ทะเลโดยตรง ตะกอนจาก WWTP (ประกอบด้วยโลหะหนักเอา) ถูกสันนิษฐานกระจายที่ fields และโลหะหนักตาม สิ้นสุดปล่อยดิน WWTP จะได้ไม่ถือว่า 100% efficient และ efficiencies specific โลหะหนักเอาใช้ใน WWTP Manfredi และคริสเตนเซ่น(2009) . โลหะหนักไม่เอาที่ WWTP ถูกสมมติปล่อยผิวน้ำ ในขณะที่โลหะหนักไม่รวบรวม leachate สิ้นสุดในน้ำบาดาล (Manfredi และคริสเตนเซ่น 2009)การปล่อยอากาศจากกระบวนการบำบัดความร้อน specific (สถานการณ์ 6 และ 7) ไม่มี แต่มีแต่ coefficients โอนย้ายองค์ประกอบตามที่ประเมินสำหรับ incinerators เสียทั่วไป (เช่นแยกส่วนขององค์ประกอบในการป้อนข้อมูลที่ออกอากาศ ดู Riber et al.,2008). The solid composition of the APC residues as shown in Table 2 was used as input. In Scenario 7, the residues were co-treated with automobile shredder residues and the transfer coefficients were applied to this mixture. The transfer coefficients were within the range 0–0.35 corresponding to incineration in a modern MSW incinerator (Riber et al., 2008; Pedersen et al., 2009).Electricity and heat consumed or substituted within the scenarios were assumed to be produced at combined heat and power plants using coal as fuel. Assumptions regarding energy may potentially be important; however the choice of coal as fuel for energy production follows common practice within LCA (for further details, refer to Fruergaard et al., 2009). The emissions and fuel consumptions at these plants were typical for Danish conditions and allocated based on energy quality, i.e. based on an assumption that electricity has a higher quality than heat and4675thereby associated with a relatively larger share of the emissions and fuel consumption (Fruergaard et al., 2009). The environmental load of electricity generation was thereby approximately six times higher than heat generation. Energy and resource consumption/ substitut
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